The research will examine patterns of herbivory in host hybrid zones. Three related projects are proposed that will elucidate for a gall wasp-leaf miner-oak system: 1) the genetic structure of oak hybrid zones, 2) patterns of herbivore density and species diversity in a variety of hybrid combinations, and 3) mechanisms responsible for variation in herbivore loads between host taxa within oak hybrid zones. A combination of correlative, experimental, and molecular genetic approaches are proposed. The correlative and experimental analyses are designed to test three mutually exclusive hypotheses regarding patterns of herbivory in host hybrid zones. The genetic analysis will introduce a new technique to plant-insect ecology, RAPD (for Random Amplified Polymorphic DNA), that will distinguish among three competing models of introgressive hybridization and host susceptibility to parasites. The work has important implications for the introduction of hybrid and genetically engineered agricultural crops, and for the conservation of endangered species threatened by interspecific hybridization.
